Embrace Your Dangerous Genome

Virginia Hughes is “sick of reading about the dangers of the genome.” So she complains over at Slate, eloquently, and I’m sick right with her.

Hughes, who blogs at National Geographic and is among our sharper followers of genetics, doesn’t mean “dangers” as in hazardous habits of actual genomes: She means the overhyped danger of “The DNA Dilemma,” as a recent Time cover called it, which is essentially whether normal regular everyday people can deal with genetic test results:

The primary question [the Time story] raises—how much information is too much information?—has been dominating commentaries about genetic testing in the medical literature.

But this is the wrong question, or at least one that’s becoming increasingly irrelevant. The personal genomics horse has bolted, and yet many paternalistic members of the medical community are still trying to shut the barn door. In doing so, they’re fostering a culture of DNA fear when what we really need is a realistic and nuanced genetics education.

Five years ago, pre-23andme, one might reasonably wonder whether people would freak out over genetic results. Your genome can bear some pretty nasty news. My own 23andme tests, for instance, revealed a gene variant that doubles my statistical risk of getting Alzheimer’s, hiking it to over 14 percent. One person close to me, meanwhile found she has a gene variant wildly raising her risk of breast and ovarian cancer. A very few people, meanwhile, may learn they carry the gene that makes it absolutely certain that, should you live to your 30s or 40s (possibly sooner), you’ll develop Huntington’s disease, which is highly unpleasant and invariably fatal.

No wonder some people worried, some 5 years ago, that such news might be more than many people can handle. Today, though, it’s clear we should set those worries aside.

To start with, most genetic testing companies offer the option to simply not learn your results on specific risk genes, such as Alzheimer’s or Huntington’s. Few choose that option; most want to know, even if there’s no cure and the news isn’t actionable. Meanwhile, much information you get is actionable. My friend who got the bad news about her breast-cancer gene, for instance, chose to have a double mastectomy and have her ovaries removed. The operation beat her up horribly, but she did it without hesitation and was immediately glad she did. The operation erased an 80% chance of getting a very nasty cancer. She’s plenty smart enough to know she was better off knowing.

Almost everyone tested agrees. As Hughes points out, a recent study of 2000 people in the New England Journal of Medicine found that lo and behold, despite that all of them got tested and received pretty complicated news, “Nobody freaked out.” We humans apparently learned a long time ago to deal with bad news and uncertainty. Hughes rightly argues we should set aside these worries and spend time thinking instead about using these genetic testing to educate people about genetics.

I agree — and in fact I’d add that one’s own genetic-test results offers a particularly memorable demonstration of something that too often gets overlooked in reporting about genetics: with very few exceptions, genes work in complicated and decidedly non-deterministic fashion.

I have ranted here before about how readily the media embraces simplistic pictures of how single genes generate even enormously complex traits and behaviors, so that a gene variant that affects a neurotransmitter or hormone that operates in scores of systems in brain and body gets boiled down to a slut gene or a feminist molecule. A personal genetic test shows the idiocy of such reductionism. It shows you that even genes affecting relatively simple physical traits, such as height or hair color, are highly probabilistic and subject to interactions with not just other genes but diet, exercise, family history, and God knows what else. I felt much less alarmed about my supposed 15% Alzheimer’s risk, for instance, when I saw that I also carry genes making it more likely I’d be short and bald. To read such news standing at over six feet and with a full head of hair delivers a particularly powerful lesson about the ambiguities of genetics.